Vacuum pan discharge valve control



June 22; 1948. MASON vAcUUM'PAN DISCHARGE VALVE cpu'moL I 2 Sheets-Sheet 1 Filed Sept. 7, 1943 JOHN E. MASON INVENTOR.

BY 9/ d W ATTORNEY June 22, 1948. J. E MASON VACUUM PAN DISCHARGE VALVE CONTROL 2 Sheets-Sheet 2 Filed Sept. '7, 1943 Fig. :9

JOHN E. WON

INVENTOR.

ATTORNEY Patented June 22, 1948 UNITED TATES FATE NT 0 F FICE 2343.628 VACUUM PAN DISCHARGE VALVE CONTROL John E. :Mas'on, Denver, 0010., assignoi' to The -stearns fioger:Manufacturing -.Company, Denver, (1010., a corporation of Colorado Application September '7, 1943, Serial No. 501,467

This invention relates to foot valves and more particularly relates to automaticallyoperated-foot valves of the type that are used in vacuum pans and the like.

in the present-day sugar refining practice, for example, there has been ail-increased adoption of the practice of boiling sugar solution to a high dry substance; Inorder to decrease the dead volume below the heating element in calandria type vacuum pans, larger foot valves are required than have been in use heretofore.

In the past. the operating mechanism used with the discharge valves has been manuall actuated, but in the valve sizes .now proposed to be used, manually actuated valves will be too cumbersome and difiicult to operate for commercial requirements.

It is an object of the present invention to provide a simple, durable and-:eflicient foot valve that is arranged for positive opening and closing movements.

Another object of the invention is to provide an automatic control for the foot valves of vacuum pansand the like.

A further .object of the invention is to pro vide a simple'and efiicient arrangement of actuating mechanism for foot valves which insures positive seating of the valve in a succession of operations. 7

Other objects reside in novel details of construction and novel combinations and arrangements of parts, all of which will be described in the course of the following description.

The accompanying drawings illustrate typical embodiments of the invention. In the drawings in .theseveral views of whichlikeparts have been designatedsimilarly,

' Fig. 1 is a schematic arrangement of acontrol mechanism .andassociated foot valve embodying features of the present invention;

Fig. 2 is a top plan view of the foot valve of Fig. 1 drawnto an enlarged scale;

Fig. 3 is a vertical section taken along theline 3-3,Fig. 2; and

i Fig. 4 is. an enlarged fragmentary section illustrating the arrangement of parts of the valve assembly inthevalve-seating position.

The arrangement of equipment constituting the foot valve'and control will be best understood by reference to Fig. 1. A. vacuum vpan V has a disctiarge outlet extending .through a rim R and a foot valve F preferably of conical shape moves through the outletintoand out of engagement with a seat on-rim R und'erthe' controlwof a-.'hydraulic lift L.

. .1 'Glaim. (Cl. 137-21) ;.In the operation of the control mechanism, the foot-valve F is moved from.an.open position to alclosed position, and subsequently ope skagain tOwpEIIliit discharge of the pan V. While: the footsval've F is in open position a pilot control switch 0 is placed in automatic, position, thereby starting pump P, and the operator gradually turns a.- .thr'ee-zway control valve A, therebyopening: the pump discharge line P'2 .to thegcylinder L and closing theiline Pl to tank T. This operation pumps oilinto the .hydrauliclif-t L' with the result :that :foot valve F, is moved into sealing engagement with :the seat :on. rim R. ll/Then :the desired pressure isattained. pressure switch S-r-l actuates magnetic switch MS which stops the-motor M driving pump P and at the same time closes-the solenoid operating valve 0. The-pressure required is variable depending'onz-theheig'ht. ofthe massecuite in the pan, .butusually :a. pressure. of 150 lbs. er sq e i c maintained .at'all times when. the pan is boiline w-ill be s'ufiici'ent.

.In the event the pressure drops totl30 lbs. per square inch, due to leakage; or other-causes-the switch Sl immediately acts to energize the magneti c'switch MS, which starts the motor M of pumpP. .Atthe same time switch S-.2 opens solenoid valve 0 and thereafter the pump P cont'inues operation .until such-time as the :pressure in the entire system again reaches 15011bs.

mAtxthlS point. switch SI operates to stop the pump, which remains. inactive thereafter until the pressure registered on a pressure gauge G has .fallenito l3.0.1bs., which induces arepetition of the operation des'cribedhereinbef ore.

-".Whenever'.the vacuumpan V is ready to be emptied; the three-way control valve A is turned manually and the pressure .in hydraulic lift -L isallowedto drop withtheoil flowing baCkrtO a storage tank T. An orificeplate is fitted. at the end of the return line to tank T and permits rapid discharge ofzthe .oil. at the beginningof thereturn movement. Thegrateof oil discharge progressively decreases as the pressure of thepan contents on the foot valve F decreases.

aconsequence oi this arrangement. the oil inthe'hydraulic-lift L acts as a-cushion preventin g excessive shock-asthe piston of the lift-comes tonrest on the bottom of the associated cylinder.

'Also-to permit-close regulation, the opening .in

the-orifice plate maybe adjusted to give .the most satisfactory operation.

' The detail of the hydraulic lift arrangement -will. be,;bestunderstood byreferenceto Figs. 2 and 3. The lift L comprises a casing 5 having a cylindrical chamber 6 into which a fluid, such as oil, is admitted through an inlet 1. A hollow piston 8 is mounted for reciprocating movement in the cylinder 6 and has its top wall 8a threadedly apertured for reception of a rod 9, which may be extended to different distances within piston 8 and is held by a jam nut 10 in such selected positions.

A housing I2 adjoins the bottom of pan V and encases the discharge outlet. This housing has an inclined bottom I3 providing a chute for the discharging matter, and an opening I4 is provided at the lower end of said chute. The rod 9 extends through a bushing mounted in inclined bottom 13 and a lubricant fitting I6 is mounted in the-bushing for lubrication to facilitate movement of the rod 9.

The foot valve F preferably comprises a hollow conical body I! flaring outwardl at the bottom as indicated at I8 in Fig. 3 and terminates inan inclined, double faced peripheral seating surface 19, as in Fig. 4. A series of equally spaced upstanding guides 20, hereshown as three in number, are formed on the exterior surface of valve F and engage the sides of rim R during movements of the valve.

On the interior of valve F a central socket member 2| is formed integrally or fixedly held thereon for reception of a ball member 22 carried at the end of rod 9. This ball and socket joint provides a self-adjustin action when the valve F is seating against rim R. which is further assisted by the action of guides which bear against rim R throughout the entire range of the opening and closing valve movements, and by a cap 21a which holds member 22 in position and allows a limited free movement of valve F.

In order to provide a satisfactory seat and seal, the rim R preferably is formed as an annular body and welded to the vacuum pan V as shown at 23 in Fig. 4. The surfaces of the dis charge outlet thus formed are shaped to conform to the double faced seating surface l9 of the valve. A dovetail recess 24 is formed in the lower seating surface of rim R and a ring 25 fitted against a shoulder 26 on the bottom of the rim clamps a resilient gasket 21 into the recess.

This gasket provides a sealing action when the valve is moved to closed position and the conforming surfaces of the valve and rim are in such a close fit that no escape of matter from the vacuum pan is permitted when the valve is seated in the opening.

This design and arrangement of parts satisfies the requirements of modern industrial practice. Larger foot valves may be provided for the calandria type and coil type vacuum pans than could be utilized if the control was dependent upon manual actuation. The provision of the hydraulic system for valve actuation insures prompt valve opening and closing movements, and the cushioning action in the piston return prevents damage to the lift structure, which otherwise might present a repair and replacement problem.

The mounting of the gasket on the underside of rim R permits periodic replacement without undue loss of time, and also increases the life of the gasket, due to the discharging material flowing over the valve F and rim R but usually around the gasket to a greater or lesser degree. Thus, the gasket is in a flow protected position. The adjustment of the rod on the lift piston permits a substantial variation in the valve stroke, and the ball and socket joint in cooperation with the design features of the rim and valve insures perfect seating in each valve operation.

The provision of the housing about the lift structure eliminates a difficulty heretofore existent in the art caused by the escape of steam into the factory building and resultant corrosion occasioned by steaming out of the pans.

The arrangement of control mechanism has the advantage of providing regulation for a single foot valve or a plurality of such valves. In Fig. 1, the three-way valve A is the control means for the foot valve F, and if a series of such valves are to be operated by the control, other three-way valves A-I and A-2 would regulate similar valves F (not shown). In such event, the threeway valve could be located where the individual discharge lines join and preferably this valve, the motor switch C and the pressure gauge G will be located at the most convenient place on the vacuum pan for access by the operator.

What I claim and wish to secure by Letters Patent is:

A discharge control for a plurality of vacuum pans and the like, which comprises a bottom for each pan and having an opening providing a discharge outlet; a foot valve mounted beneath each pan for vertical movement into and out of sealin engagement with the respective outlet; a hydraulic lift connected with each foot valve for elevating said valve into sealing engagement with the outlet; a source of fluid under pressure; a discharge line; a separate line leading to each hydraulic lift; a pluralit of three-way valves, each connected with a lift line and also with said pressure and discharge lines, said valves being movable to a position connecting the respective lift line with said pressure line, and to a second position connecting the respective lift line with said discharge line; means associated with said pressure line for maintaining fluid pressure therein at or above a predetermined value; and flow restricting means in said discharge line for restraining the initial opening movement of a lift valve when the three-way valve associated therewith is turned to a position connecting the respective lift line with discharge line.

JOHN E. MASON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 415,469 Porter Nov. 19, 1889 930,101 Stevens Aug. 3, 1909 953,260 Dixon Mar. 29, 1910 1,010,890 Fulton Dec. 5, 1911 1,097,681 Shaughnessy May 26, 1914 1,150,779 Lord Aug. 17, 1915 1,191,481 Scoville July 18, 1916 1,231,280 Metten June 26, 1917 1,341,319 Hodges May 25, 1920 1,604,428 Veeder Oct. 26, 1926 1,615,643 Mickey Jan. 25, 1927 1,699,109 Jones Jan. 15, 1929 1,714,182 McNulty May 21, 1929 1,763,593 Nelson June 10, 1930 1,847,343 Jackson Mar. 1, 1932 1,922,874 Tymstra Aug. 15, 1933 2,211,318 Camerota Aug. 13, 1940 2,239,481 Christensen Apr. 22, 1941 2,241,294 Carreras May 6, 1941 

